Crust: In bowl, combine graham cracker crumbs, sugar and cinnamon; stir in butter.
Press evenly onto bottom and halfway up sides of 10-inch (3 L) spring form pan.
In bowl, beat cream cheese, sugar and cornstarch until fluffy.
Beat in eggs, one at a time.
Fold in blackberry puree; pour into crust.
Bake in 325Ã‚Â°F (160Ã‚Â°C) oven for about 50 minutes or until set around edge and still slightly wobbly in center.
Remove to rack.
Immediately run knife around inside of pan.
Let cool completely to room temperature.
Cover and refrigerate until chilled.
Garnish: Remove side of pan; place cake on serving plate.
Garnish with blackberries and whipped cream.